A known implement having at least two axes and which is operated by providing control about the axis is a loader/bucket arrangement of the type used on tractors, skid steer vehicles, articulated vehicles, and tracked vehicles. Such an arrangement typically includes two arms pivotally attached to the vehicle at one end of the arms and a bucket pivotally attached at the distal end of the arms. The arms are typically pivoted relative to the vehicle by hydraulic cylinders appropriately attached thereto to raise and lower the bucket. The bucket is pivoted relative to the arms by hydraulic cylinders appropriately attached thereto.
The power to actuate the hydraulic cylinders which produce the pivoting motion of the loader arms and bucket about their respective pivot axes is provided by hydraulic fluid supplied to the cylinders by an appropriate pump or pumps. The flow of hydraulic fluid is controlled by valves which may be manually, electrically, or electro-mechanically operated.
For many uses of loaders, it is desirable to maintain the orientation of the bucket relative to the surface upon which the associated vehicle is operating while the loader arms are being raised or lowered. In certain conventional systems, to achieve this result, the operator must control the valve for the hydraulic cylinders of the loader arms ("Arm Valve") while simultaneously controlling the valve for the hydraulic cylinder of the bucket ("Bucket Valve"). This simultaneous control of the Arm and Bucket Valves requires that the operator maintain visual contact with the bucket, which on certain vehicles is difficult. In many situations, the vehicle and loader configuration will not permit the operator to properly determine the orientation of the bucket through the full range of motion of the bucket.
In response to this need for a loader arrangement which can be operated to maintain the orientation of the bucket relative to the surface over which the bucket is being raised and lowered, loaders have been designed to include self-leveling linkages which serve to maintain the orientation of the bucket. Alternatively, some loaders have been designed to combine the operation of the Arm and Bucket Valves to provide improved bucket orientation control. One problem with many of the presently used arrangements for bucket orientation control is the complexity of such arrangements. This complexity increases cost and, in most cases, reduces reliability. Another problem with certain existing systems is the utilization of operator controls which are not easily and efficiently manipulated by the operator to achieve desired loader operations.
In view of the need for improved bucket control and the drawbacks with many existing systems, it would be desirable to provide an improved electronic system useable by an operator to effectively control the orientation of the arms and bucket of a loader or other implement requiring coordinated control about at least two axes.